Implemented DatabaseConector constructor

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector Open Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector Close Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector Insert Contact Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector Update Contact Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector getAllContacts Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Refactored to extract contactsTable as a variable

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector getOneContact Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseConnector deleteContact Method

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Aligned comments.

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>
Implemented DatabaseOpenHelper private nested class.

Signed-off-by: Luke GJ Potter <lukegjpotter@gmail.com>